KR20120050995A - Diffuse reflective illuminator - Google Patents

Abstract

The apparatus includes a curved light reflecting surface comprising a pair of opposing curved edges and a pair of opposing longitudinal edges extending between corresponding disadvantages of the opposing curved edges; A pair of reflecting surfaces, each reflecting surface attached to a corresponding edge of the curved edge; One or more flanges connected to one of said pair of longitudinal edges and projecting toward opposite longitudinal edges; And one or more light sources mounted on the one or more flanges. Other embodiments and aspects are also disclosed and claimed.

Description

Diffuse Reflective Illuminator {DIFFUSE REFLECTIVE ILLUMINATOR}

The present invention relates generally to lighting systems, and in particular but not exclusively, to diffuse reflective illuminators.

Priority claim

This application claims priority to US patent application Ser. No. 12 / 497,265, filed on July 2, 2009, under Section 8 of the Patent Cooperation Treaty (PCT).

Optical data-reading systems have become an important and very common tool for the tracking of many different kinds of items, and machine-vision systems have become a major tool for identifying and inspecting parts. It became an important tool for tasks. Both optical data reading systems and machine version systems capture two-dimensional digital images of optical symbols (for optical data reading systems) or components (for typical machine vision systems), and then extract the information contained in the images to Proceed with the analysis. One difficulty known in machine vision systems is to ensure that the camera acquires an accurate image of the object; If the camera is unable to obtain an accurate image of the object, the camera may not be able to use to decode or analyze the image or may have difficulty doing so.

One of the difficulties in acquiring accurate images is to ensure proper illumination of the object being imaged. Problems can always occur when lighting is the wrong type or has a problem such as nonuniformity. Illuminators exist to provide illumination for optical data reading systems and machine vision systems, but have known disadvantages. Conventional fixtures are usually round, making them larger than necessary and difficult to manufacture. The rounded shape also makes the lighting pattern different from the imager's field of view, which can lead to uneven illumination, especially near the edges of the image. Other kinds of existing fixtures may reduce some of these drawbacks but do not overcome most or all of them.

DETAILED DESCRIPTION OF THE EMBODIMENTS Reference will now be made to the embodiments of the present invention, which are non-limiting and not exhaustive, with reference to the following drawings, wherein like reference numerals refer to similar parts throughout the several figures unless otherwise specified.
1A is an exploded perspective view of an illuminator embodiment.
FIG. 1B is an assembled perspective view of the illuminator embodiment shown in FIG. 1A.
2A is a side view of the illuminator embodiment shown in FIGS. 1A and 1B.
FIG. 2B is a front view of the illuminator embodiment shown in FIGS. 1A and 1B, seen from section line BB of FIG. 2A.
FIG. 2C is a bottom view of the illuminator embodiment shown in FIGS. 1A and 1B, seen from section line CC of FIG. 2A.
2C is a side view of another illuminator embodiment that includes a bottom cover.
3A-3C are top views of the bottom of another illuminator embodiment.
4A-4F are side views of another illuminator embodiment.
5A-5C are side views of several different embodiments of flanges for illuminators.
6 is a schematic diagram of an imaging system including an illuminator of an embodiment.

Embodiments of apparatus, systems, and methods for diffuse reflective illumination are described. In the following description, numerous details are set forth in order to provide a thorough understanding of embodiments of the present invention. However, one of ordinary skill in the art appreciates that one or more of such details may be practiced or that the present invention may be practiced using other methods, components, materials, and the like. In other instances, well-known structures, materials, or operations are not shown or described in detail, but are still within the scope of the present invention.

As used throughout this specification, the expression "one embodiment" or "an embodiment" means that a specific feature, configuration, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the expressions "in one embodiment" or "in an embodiment" herein are not necessarily all referring to the same embodiment. In addition, specific features, configurations, or characteristics may be combined in any suitable manner in one or more embodiments.

1A and 1B together show an embodiment of the illuminator 100, FIG. 1A is an exploded view, and FIG. 1B is an assembled view. Illuminator 100 is a curved light-refecting surface 102 (hereafter surrounded by curved edges 103, 105 and also by longitudinal edges 107, 109). , Also referred to as "curved face" or simply "face"). For this application, "curved edges" include all edges that are not single straight lines and include, without limitation, smooth and continuous curves as well as curves consisting of multiple straight or non-linear portions, whether continuous or not. do. In the illustrated embodiment, the curved face 102 is concave, but in other embodiments can be convex or any combination of concave and convex.

An end cap 104 is attached to the curved edge 103, while an end cap 108 is attached to the curved edge 105. The flange 112 is coupled to the longitudinal edge 107 and protrudes from the edge 107 toward the opposite longitudinal edge 109. Likewise, flange 114 is coupled to longitudinal edge 109 and projects toward opposite longitudinal edge 107. Although not visible in FIGS. 1A and 1B, a light source 118 facing the surface 102 is mounted on the sides of the flanges 112, 114 (see, for example, FIGS. 2A-2C). An optional imaging aperture 116 may be formed in the curved light reflecting surface 102.

Each longitudinal edge 107, 108 extends from the disadvantage of the curved edge 103 to the disadvantage of the corresponding curved edge 105 to form the face 102. In the illustrated embodiment, the curved edges 103, 105 are all the same size and shape, and the longitudinal edges 107, 109 are straight, which is substantially shaped in the shape of the face 102 with the semicircle open to the right. It is like an open right semi-circular cylinder. In other words, the curved light reflecting surface 102 in the illustrated embodiment is from the curved edge 103 which turns straight across the space until it reaches the curved edge 105 or becomes the curved edge 105. Occurs. However, in other embodiments, the curved edges 103, 105 may be other than semicircular (see FIGS. 4A-4E), while in other embodiments the curved edges 103, 105 may be of the same size and / or. It does not need to be in the form or shape, nor do the longitudinal edges 107, 109 need to be the same size and / or shape.

End caps 104 and 108 should be attached to curved edges 103 and 105 to substantially cover the open end of curved light reflecting surface 102. In the illustrated embodiment, the end caps 104 and 108 are substantially the same as the open end of the face 102 curved cross-section, but in other embodiments, the end caps 104 and 108 will be exactly the same shape as the open end. There is no need. For example, one or both of the end caps 104, 108 may be square as long as it covers the substantially curved face 102.

2A shows a side view of the illuminator 100. In the illustrated embodiment, the curved light reflecting surface 102 is semicircular in cross section when viewed from the side (ie, the curved edges 103, 105 are all semicircular), and the curved surface 102 is on the right side. Make it resemble an open semicircular column. In the illustrated embodiment, the curved face 102 bends the lamina into a suitable shape to produce the desired shape of the face 102. In one embodiment, the thin plate may be a sheet metal, but in other embodiments the thin plate is made of another material, such as a sheet of plastic or a kind of composite. In yet another embodiment, face 102 may be formed differently. For example, in one embodiment face 102 may be made by machining a solid block of metal, plastic, wood, or some kind of composite.

The curved light reflecting surface 102 is configured to reflect and / or diffuse incident light from the light source 118. The curved face 102 has a height H and a width W, both of which are selected based on the specific application and its requirements. In certain applications, curved surface 102 must also have appropriate physical and / or optical properties, such as color, texture, and reflectance, to cause the desired reflection and diffusion. In one embodiment, the physical and / or optical properties of face 102 may be tailored to enhance or supplement the optical properties of light source 118, while in other embodiments the physical and / or optical properties of face 102 may be tailored to a light source. It can be used to alter the optical properties of the light emitted by 118. For example, in an embodiment where the light source 118 emits white light, by applying an appropriately colored coating to the curved light reflecting surface 102, the white light from the light source 118 causes the opening 120 to exit. The color of light exiting the fixture can be filtered out of white.

The material that makes up the surface 102 may already have suitable physical and / or optical properties so that no additional treatment is required once the curved light reflecting surface 102 is formed. For example, in an embodiment in which the sheet 102 is bent around a mold to form the surface 102, the sheet may already be made of plastic that already has the appropriate color, texture, and reflectivity, which is formed after the surface is formed. That means there is nothing more to do. In other embodiments where the material does not have the required color, reflectance, or texture, such as when the curved surface 102 is formed of metal, suitable physical and / or optical properties may be applied to the later curved light reflecting surface 102. Additional processing may be required to grant. In one embodiment, a coating such as paint may be applied to the face. In other embodiments, another treatment may be to place a sheet of material with accurate physical and / or optical properties on the curved light reflecting surface 102 and secure with an adhesive.

The flange 112 has a width F and is connected to the longitudinal edge 107 and protrudes from the edge 107 toward the opposite longitudinal edge 109. Likewise, the other flange 114 has a width F, which is connected to the longitudinal edge 109 and projects toward the opposite longitudinal edge 107. In the illustrated embodiment, a light source 118 is mounted on the sides of the flanges 112, 114 facing the face 102. In one embodiment, the flanges 112, 114 may be formed integrally with the face 102, which means that the face 102 and the flanges 112, 114 are formed of a single piece of material. do. In other embodiments, one or both of the flanges 112, 114 may include adhesives, fasteners, welding, soldering, brazing, or the like, on the face 102 or on the material forming the face 102. By various methods, it can be a separate piece to be attached.

While the illuminator 100 is in operation, the light source 118 emits light incident on the curved surface 102. Light from each light source 118 is reflected and diffused such that as it strikes face 102, uniform diffused light exits illuminator 100 through opening 120.

2b shows a side cross-sectional view of the illuminator 100. The curved light reflecting surface 102 has a length L, which means that the curved edges 103, 105 are separated by L; Since the illuminator 100 has a height H and a width W, the length L can be selected based on the requirements of the application. End cap 104 includes reflective surface 106 and end cap 108 includes reflective surface 110. End caps 104, 108 are attached to the curved edge of face 102 having reflective surfaces 106, 110 that are parallel or substantially parallel to each other and face each other. Thus, the reflecting surface 106 and the reflecting surface 110 are also approximately separated by a distance L. However, in other embodiments, the reflective surfaces 106, 110 need not be parallel and may be oblique to each other.

In one embodiment, the reflective surfaces 106, 110 are mirrors, but in other embodiments the reflective surfaces 106, 110 may be other types of surfaces whose reflectance is the same as or less than the mirror. In one embodiment, the reflective surfaces 106, 110 are first surface mirrors, which means that the reflective surface should be the surface where the incident light first meets. In other embodiments, other types of mirrors may be used. The reflective surface 106 and the reflective surface 110 can be formed in different ways. For example, when the end caps 104 and 108 are metal, the reflective surfaces 106 and 110 can be formed by polishing the appropriate surface of each end gap. In other embodiments, reflective coatings may be applied to the end caps 104 and 108, for example, by securing or spraying a sheet of reflective material on the appropriate surface of each end cap. In yet other embodiments, more complex methods such as electroplating may be used.

 The flanges 112, 114 extend over the entire length L of the curved surface 102 between the reflective surface 106 and the reflective surface 110. The light source 118 is located on the flanges 112, 114, with a provision for delivering power to the light source. The type and number of light sources 118 will depend on the type of light source used as well as the desired light properties such as power requirements and color and uniformity of the application. In one embodiment, the light source 118 may be a light emitting diode (LED), but in other embodiments the light source 118 may be another kind of light source, such as an incandescent or halogen bulb. In another embodiment, the light sources 118 need not be all the same kind, but instead may include a combination of two or more different kinds of light sources. The spacing between the light sources will generally depend on the number of light sources 118 and the length of the flanges or flanges on which the light sources 118 are mounted. In the illustrated embodiment, the light sources 118 are evenly spaced apart s, but in other embodiments the light sources 118 need not be evenly spaced apart.

2c shows a bottom view of the illuminator 100. The end caps 104, 108 are both attached to the curved surface 102 with the reflective surfaces 106, 110 facing each other and at approximately a distance L apart. In the illustrated embodiment, each flange 112, 114 has the same width F and substantially spans the total distance L between the reflective surfaces 106, 110. In another embodiment, the flanges 112, 114 need not necessarily be the same width F, but instead may have different lengths (see FIG. 3C). In yet another embodiment, the flanges 112, 114 may have different configurations (see FIGS. 5A-5C), may have a length less than L, not necessarily the same length L, but instead different lengths. It may have (see Fig. 3c). In other embodiments, it is also possible to have several individual flanges over the distance between the reflecting surface 106 and the reflecting surface 110 instead of a single flange. Another embodiment may include only one of the flanges 112, 114, and the length of the existing flange may be longer or shorter than the length L.

2D shows a side view of another embodiment of illuminator 150. Illuminator 150 is similar to illuminator 100 in most respects. The main difference is that the illuminator 150 includes a cover 122 across the bottom of the illuminator to prevent contaminants or other objects from entering the illuminator through the opening 120 and damaging the internal components. . In the illustrated embodiment, the cover 122 is shown mounted on the outside of the flanges 112, 114, but in other embodiments the cover 122 may be mounted on the inside of the flange or on another portion of the fixture. In one embodiment the cover 122 is transparent and very thin to avoid compromising the optical uniformity of the illuminator, but in other embodiments, the thickness of the cover 122 may be thicker or thinner, and the cover 122 ) May be made of translucent material to provide additional diffusion. In another embodiment, the cover 122 may include an anti-reflective coating on the inside, outside, or both inside and outside.

3A-3C show several different embodiments of illuminators. 3A shows an illuminator 300 similar to illuminator 100 in most respects. The main difference between illuminator 300 and illuminator 100 is that there is no imaging aperture in illuminator 300. Illuminator 300 may be used in an application where the illuminator is a stand-alone unit separate from the imaging device. 3B also shows an illuminator similar to illuminator 100 in most respects. The main difference between illuminator 325 and illuminator 100 is that there are multiple imaging apertures in illuminator 325. These are vertices or peaks of face 102 as well as apertures 326 located on or near the centerline of curved face 102 (eg, at or near vertices or cusps). An aperture 328 positioned away from it. 3C shows another illuminator 350 similar to illuminator 100 in most respects. The main difference between the illuminator 350 and the illuminator 100 is that the lengths of the flanges 352, 354 in the illuminator 350 are different and do not span the entire distance between the reflecting surfaces 106, 110. Of course, any of the illuminators 300, 325, 350 can have any curved surface in shape as shown in FIGS. 4A-4E, and also features of the illuminators 300, 325, 350. Can be combined with each other.

4A-4F are cross-sectional views of several different embodiments of illuminators. 4A shows that the two curved edges of the curved face 402 are semi-elliptical and symmetric about the centerline 401, so that the right side has a vertex or peak 404 that aligns the curved face 402 with the centerline. The embodiment which makes this open half-ellipse pillar is shown. 4B shows that the two curved edges of the curved face 406 are parabolic and symmetric about the centerline 401 such that the right side has a vertex or peak 408 that aligns the curved face 406 with the centerline. Embodiments are made of open parabolic columns. 4C shows that the curved edges of the curved surface 410 are square and symmetric about the centerline 401 such that the right side is open with vertices or peaks 412 aligning the curved surface 410 with the centerline. The example which makes a square pillar is shown. 4D shows that the two curved edges of the curved face 414 are faceted (ie, composed of a plurality of line segments) and symmetric about the center line 401 such that the curved face 414 is centered with the center line. An embodiment is made of an open polyhedral column with the right side having a straight vertex or peak 416.

4E shows that the curved edges of curved face 418 are skewed parabola and not symmetric about center line 401, such that curved face 418 is to the right with vertices or peaks off center line. The example which makes an oblique parabolic column is shown. Finally, FIG. 4F shows that the curved edges of curved surface 418 are compound curves and, as shown, an M-shaped curve symmetric about centerline 401 and having two peaks 426, 428. The example which is (44) is shown. In other embodiments with complex curves, the curves need not necessarily be symmetric about the centerline 401. For example, in another embodiment, the composite curve may be oblique, as shown in FIG. 4E, or the peaks 426, 428 need not necessarily be the same height.

4A-4F are not intended to provide a complete catalog of possible forms for curved faces. In other embodiments, other forms than those shown may be used. For example, in other embodiments, any polynomial function may be used to form curved surfaces, while in other embodiments, other types of functions may be used, such as exponential, logarithmic, or hyperbolic functions.

5A-5C show another embodiment of a flange that can be used in another embodiment of the illuminator. 5A shows an embodiment 500 in which a flange 504 is connected to a curved face 102. In the illustrated embodiment, the flange 504 protrudes from the longitudinal edge of the substantially flat and curved face 102. The flange 504 has a width F. In general, W may be sized such that direct light from light source 118 does not exit through opening 120 (see, eg, FIG. 2A); In other words, the width F is that all light exiting the illuminator is reflected and diffused by the curved light reflecting surface 102 and none of the light exiting the aperture 120 comes directly from the light source 118. So that it is sized.

5B shows another flange embodiment 525 with a free edge (ie, edge not connected to curved face 102) with an upturned portion 508. The upwardly directed portion 508 may help prevent light from the light source 118 from exiting the illuminator directly through the aperture 120 (eg, see FIG. 2A). The presence of the upward facing portion 508 can reduce the width F of the flange while preventing the light from the light source 118 from leaving the illuminator immediately. In one embodiment, the upward portion 508 may extend along the entire length of the flange, while in other embodiments the upward portion 508 may only exist along portions of the length of the flange.

5C shows a flange embodiment 550 with a baffle 512 positioned at or near the free edge (ie, edge not connected to the curved face 102). In one embodiment, the baffle 512 may be made of an opaque material, while in other embodiments the baffle 512 may be made of a translucent or transparent material. In yet another embodiment, the baffle 152 may be made of a combination of two or more of an opaque, translucent, or transparent material. By appropriately selecting the size, location and material of the baffle 512, the baffle 512 will prevent light from the light source 118 from exiting the illuminator directly through the aperture 120 (eg, see FIG. 2A). To help. The presence of the baffle 512 allows to reduce the width F of the flange while still preventing the light from the light source 118 from leaving the illuminator immediately. In one embodiment, the baffle 512 may extend along the entire length of the flange, while in other embodiments the baffle 512 may only exist along a portion of the length of the flange.

6 shows an imaging system 600 that includes an illuminator 100, and other embodiments of the imaging system 600 may, of course, be substituted for any of the other illuminators described herein. Imaging system 600 includes a housing 602 in which illuminator 100 and camera 604 are located. In addition to the camera 200 and illuminator 100, the imaging system 600 includes a signal conditioner 612 connected to the image sensor 610, a processor 614 connected to the signal conditioner 612, and a processor 614. It includes an input / output unit 616 connected to. Although not shown, an internal or external power supply supplies power to the components in the housing 602. In one embodiment, imaging system 600 may be a small portable handheld system, while in other embodiments, imaging system 600 may be a fixed-mount imaging system.

Illuminator 100 is positioned within housing 602 such that opening 120 faces the object to be illuminated and imaged. In the illustrated embodiment, the object to be illuminated and imaged is an optical symbol, such as a barcode or matrix code 618 on face 620, but in other embodiments the object may be part or surface of a component under machine vision inspection. have. The curved face 102 extends into the interior of the housing 602 and includes an imaging aperture 116 near its peak or vertex. When power is supplied to the light source 118, the light from the light source 118 enters the curved light reflection surface 102, which then reflects and diffuses the light so that the opening ( Directing toward 120, light exits the illuminator and falls to object 618 and / or surface 620.

Camera 604 includes optics 609 coupled to image sensor 610. In one embodiment, optics 608 includes one or more reflective lenses, while in other embodiments optics 608 may include one or more refractive, reflective or diffractive optics. In one embodiment, image sensor 610 includes a CMOS image sensor, but in other embodiments other types of image sensors, such as CCDs, may be used. Camera 604 and optics 608 are positioned in housing 602 such that optics 608 are optically aligned with imaging aperture 116 in curved surface 102. Optical alignment of the optics 608 and imaging aperture 116 allows the optics 608 to focus the image of the object 618 on the image sensor 610 and the image sensor 610 It allows to capture an image of the object 618 while at the same time allowing the illuminator 100 to illuminate the object.

The signal conditioner 612 is connected to the image sensor 610 to receive and condition signals from the pixel array within the image sensor 610. In other embodiments, signal conditioner 612 may include various signal conditioning components, such as filters, amplifiers, offset circuits, automatic gain controls, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and the like. The processor 614 is connected to the signal conditioner 612 to receive a conditioned signal corresponding to each pixel in the pixel array of the image sensor 610. The processor 614 may include a processor or memory, as well as logic or instructions for processing image data to generate a final digital image and to analyze and decode the final image. In one embodiment, the processor 614 may be a general purpose processor, but in another embodiment, the processor 614 may be an Application Specific Integrated Circuit (ASIC) or a Field-Programmable Gate Array (FPGA).

The input / output circuit 616 transmits the image data or decoded information to another component (not shown) that can store, display, further process, or otherwise use the image data or decoded information. It is connected to the processor 614. In particular, input / output circuitry 616 may include a wired or wireless connection to a processor, memory, storage, and one or more other computers, displays, or other components.

In the illustrated embodiment, elements 612, 614, 616 are shown to be housed with camera 601 and illuminator 100, while in other embodiments, elements 612, 614, 616 are external to housing 602. It may be located. In yet another embodiment, one or more of the elements 612, 614, 616 may be integrated into the image sensor 610.

The foregoing description of the illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise form disclosed. While specific embodiments of the invention, and examples of the invention have been described herein for purposes of illustration, those skilled in the art will recognize that many equivalent modifications are possible within the scope of the invention. Such changes may be made to the invention in light of the above detailed description.

The terminology used in the following claims should not be construed as limiting the invention to the specific embodiments disclosed in the specification and the claims. More precisely, the scope of the invention is defined solely by the claims below and should be interpreted in accordance with the established doctrine of claim interpretation.

Claims (35)

A curved light reflection surface comprising a pair of opposing curved edges and a pair of opposing longitudinal edges extending between corresponding disadvantages of the opposing curved edges;
A pair of reflecting surfaces, each reflecting surface attached to a corresponding edge of the curved edge;
One or more flanges connected to one of said pair of longitudinal edges and projecting toward opposite longitudinal edges; And
At least one light source mounted on the at least one flange
/ RTI > The method of claim 1,
And a light-diffusing coating on the light reflection surface. The method of claim 1,
And the pair of reflective surfaces are planar and parallel to each other. The method of claim 1,
And the pair of opposing longitudinal edges is co-planar. The method of claim 1,
And an imaging aperture within said light reflection surface. The method of claim 1,
The light reflection surface is smooth and continuous The method of claim 1,
The curved side is faceted. The method of claim 1,
Wherein the shape of the opposing curved edge is one of a semicircle, parabola, hyperbola, semi-ellipse or oblique parabola. The method of claim 1,
The one or more light sources comprise one or more light bulbs or light emitting diodes (LEDs). The method of claim 1,
The free end of the flange is bent at an angle to the rest of the flange. The method of claim 1,
And a baffle located at or near the free end of the flange. The method of claim 11,
And the baffle is transparent, translucent or opaque. A curved light reflecting surface comprising a pair of opposing curved edges and a pair of opposing longitudinal edges extending between corresponding disadvantages of the opposing curved edges and having an imaging aperture therein ;
A pair of reflecting surfaces, each reflecting surface attached to a corresponding edge of the curved edge;
One or more flanges connected to one of said pair of longitudinal edges and projecting toward opposite longitudinal edges; And
At least one light source mounted on the at least one flange
Light emitting device comprising a; And
A camera comprising imaging optics coupled to the light emitting device and optically coupled to the imaging aperture.
/ RTI > The method of claim 13,
And a light diffusing coating on the light reflecting surface. The method of claim 13,
The light diffusing surface is smooth and continuous. The method of claim 13,
The curved side is faceted. The method of claim 13,
And the pair of reflective surfaces are planar and parallel to each other. The method of claim 13,
And the pair of opposing longitudinal edges are coplanar. The method of claim 13,
The form of the opposing curved edge is one of a semicircle, parabola, hyperbola, semi-ellipse or oblique parabola. The method of claim 13,
The one or more light sources comprise one or more light bulbs or light emitting diodes (LEDs). The method of claim 13,
Further comprising signal conditioning circuitry coupled to the camera. The method of claim 21,
And an image processor coupled to the signal conditioning unit and the camera. The method of claim 22,
And an input / output unit coupled to the processor. Forming a curved light reflecting surface comprising a pair of opposing curved edges and a pair of opposing longitudinal edges extending between corresponding disadvantages of the opposing curved edges;
Attaching a pair of reflective surfaces to corresponding edges of the curved edges;
Forming at least one flange on one of the pair of longitudinal edges protruding toward an opposite longitudinal edge; And
Mounting at least one light source on the at least one flange
≪ / RTI > 25. The method of claim 24,
And forming a light diffusion coating on the light reflection surface. 25. The method of claim 24,
And the pair of reflective surfaces are planar and parallel to each other. 25. The method of claim 24,
And the pair of opposing longitudinal edges are on the same plane. 25. The method of claim 24,
And forming an imaging aperture within the curved light diffusing surface. 25. The method of claim 24,
And the light reflecting surface is smooth and continuous. 25. The method of claim 24,
The curved side is faceted. 25. The method of claim 24,
Wherein the shape of the opposing curved edge is one of a semicircle, parabola, hyperbola, semi-ellipse or oblique parabola. 25. The method of claim 24,
The one or more light sources comprise one or more light bulbs or light emitting diodes (LEDs). 25. The method of claim 24,
Bending the free end of the flange at an angle to the rest of the flange. 25. The method of claim 24,
Positioning a baffle at or near the free end of the flange. The method of claim 34, wherein
And the baffle is transparent, translucent or opaque.

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